Relationships between paraspinal muscle morphology and neurocompressive conditions of the lumbar spine: a systematic review with meta-analysis

Abstract

BackgroundIndividual study results have demonstrated unclear relationships between neurocompressive disorders and paraspinal muscle morphology. This systematic review aimed to synthesize current evidence regarding the relationship lumbar neurocompressive disorders may have with lumbar paraspinal muscle morphology.MethodsSearches were conducted in seven databases from inception through October 2017. Observational studies with control or comparison groups comparing herniations, facet degeneration, or canal stenosis to changes in imaging or biopsy-identified lumbar paraspinal muscle morphology were included. Data extraction and risk of bias assessment were performed by review author pairs independent of one another. Morphological differences between individuals with and without neurocompressive disorders were compared qualitatively, and where possible, standardised mean differences were obtained.ResultsTwenty-eight studies were included. Lumbar multifidus fiber diameter was smaller on the side of and below herniation for type I [SMD: −0.40 (95% CI = −0.70, −0.09) and type II fibers [SMD: −0.38 (95% CI = −0.69, −0.06)] compared to the unaffected side. The distribution of type I fibers was greater on the herniation side [SMD: 0.43 (95% CI = 0.03, 0.82)]. Qualitatively, two studies assessing small angular fiber frequency and fiber type groupings demonstrated increases in these parameters below the herniation level. For diagnostic imaging meta-analyses, there were no consistent differences across the various assessment types for any paraspinal muscle groups when patients with herniation served as their own control. However, qualitative synthesis of between-group comparisons reported greater multifidus and erector spinae muscle atrophy or fat infiltration among patients with disc herniation and radiculopathy in four of six studies, and increased fatty infiltration in paraspinal muscles with higher grades of facet joint degeneration in four of five studies. Conflicting outcomes and variations in study methodology precluded a clear conclusion for canal stenosis.ConclusionsBased on mixed levels of risk of bias data, in patients with chronic radiculopathy, disc herniation and severe facet degeneration were associated with altered paraspinal muscle morphology at or below the pathology level. As the variability of study quality and heterogeneous approaches utilized to assess muscle morphology challenged comparison across studies, we provide recommendations to promote uniform measurement techniques for future studies.Trial registrationPROSPERO 2015: CRD42015012985Electronic supplementary materialThe online version of this article (10.1186/s12891-018-2266-5) contains supplementary material, which is available to authorized users.

Assessing Lumbar Paraspinal Muscle Cross-sectional Area and Fat Composition with T1 versus T2-Weighted Magnetic Resonance Imaging: Reliability and Concurrent Validity.

“…All muscle and fat within these boundaries were included. These measurement parameters accord with recent recommendations for assessing paraspinal muscle morphology [14,31]. A detailed description of the outlining parameters applied, including methods for addressing variations from the "normal" boundary appearances, can be found in Additional le 1.…”

Evaluation of lumbar multifidus muscle in patients with lumbar disc herniation: are complex quantitative MRI measurements needed?

“…A meta-analysis of 28 studies that evaluated the impact of lumbar disc herniation, facet degeneration, or canal stenosis on lumbar paraspinal muscle morphology, concluded that disc herniation and severe facet degeneration were associated with altered paraspinal muscle morphology at, or below, the pathology level. 31 However, the authors highlighted the different measurement techniques in these studies and the need for a consensus on measurement methods, and recommend measurement techniques for standardization. 31 The authors also noted that normalization of brightness for pixel intensity assessment is a matter of importance to reduce variability between equipment and facilities.…”

Age-related changes in trunk muscle activity and spinal and lower limb kinematics during gait

“…Further, due to the morphological complexity of thoracolumbar muscles where intramuscular variations like fibre length exist within and between vertebral levels and regions, we recommend that intra-muscular regions be considered separately and at multiple vertebral levels to identify age-related modifications to function. New evidence is pointing the importance of specific intervertebral level to muscle composition in neurocompressive (and degenerative) conditions of the lumbar spine,[ 54 ] which age strongly influences.…”